Anti-Virus That Takes Less Memory and Very Effective

http://www.threatfire.com/ Made by the developers of the popular tool Spyware Doctor, ThreatFire is an anti-spyware utility that works well with other anti-virus tools and enhances the protection they offer. Plus, the software takes very little memory. The scan is faster than Norton Anti -Virus and Avira AntiVir. So I am using it.